present invention relates to a method and apparatus for the treatment of molten metals with a volatile treating agent and, more particularly, a method and apparatus for treating molten metal with magnesium in the form of pure magnesium or magnesium alloys.
The treatment of molten metal melts using pure magnesium or magnesium containing prealloys is well-known in the art. There have, however, been a number of serious disadvantages associated with known treatment methods. Specifically, when treating molten metal melts with prealloys containing low percentages of magnesium, the overall product costs are high due to their limited scope of application. In addition, during treatment, undesirable elements are brought into the melt.
One known process for treating molten metals is the "sandwich process" wherein prealloys containing low percentages of magnesium are used for the treatment of molten metal. In accordance with the process, a predetermined amount of prealloy is introduced into an open treatment vessel and subsequently molten metal is poured over the prealloy into the vessel. Due to the volatile reaction between magnesium and the molten melt, this type of process cannot be performed with prealloys which contain 40% by weight magnesium or greater.
Naturally, it would be highly desirable to provide a method and apparatus for the treatment of metal melts with magnesium which overcome the disadvantages noted above and which are economical in production and maintenance.
Accordingly, it is a principal object of the present invention to provide a process and apparatus for the treatment of molten melts with volatile treating agents.
It is a particular object of the present invention to provide a method and apparatus as aforesaid wherein molten melts may be treated with pure magnesium and prealloys containing a high percentage of magnesium.
Further objects and advantages of the present invention will appear hereinbelow.